For many years school buses have been equipped with safety units, such as crossing gates and stop signs, rotatably mounted to the school bus and movable between a retracted position adjacent to the body of the bus and an extended position extending outwardly from the body of the bus. A stop sign safety unit alerts drivers of nearby vehicles that children are either entering or exiting the school bus whereas a crossing gate safety unit forces children to walk at a safe distance from the front of the bus such that the school bus driver can see the children free from the obstruction created by the bus body. U.S. Ser. No. 08/061,722 filed May 17, 1993, of common assignee herewith, provides an example of school bus stop signs and crossing gates.
In U.S. Pat. No. 5,036,307 to Reavell et al. a school bus stop sign safety unit comprising a conventional octagonal plate having indicia defining the word STOP is disclosed. The stop sign includes a pair of flasher lights which are caused to flash periodically to provide a highly visible warning to the drivers of nearby vehicles. The circuitry which causes the flashers to flash is conventionally located in a remote location from the stop sign, usually within the school bus body or the housing which mounts the stop sign to the school bus. The flashers on the school bus stop sign use incandescent light bulbs. Incandescent light bulbs are cumbersome and bulky and have a tendency of burning out thereby requiring frequent replacement. It would be an improvement over the prior art school bus safety units to illuminate the safety units using light emitting diodes (L.E.D.'s) rather than incandescent light bulbs. L.E.D.'s have a much longer life than conventional incandescent bulbs and thus would substantially reduce maintenance cost and safety problems created by incandescent bulbs. Additionally, L.E.D.'s are encapsulated in a durable compact transparent plastic package resistant to the harsh operating environment of a school bus.